Alternating current (AC) voltage generating arrangements are required in diverse cases. Examples include the excitation of plasma, induction heating or mains feed-in. Such loads are also referred to below as “load with dynamic load impedance”. Dynamic load impedance is intended to be understood to refer to an impedance which has the property of changing within one or a small number of periods of the AC voltage produced. Some AC voltage generating arrangements which, with high powers greater than 10 kW, produce frequencies greater than 10 Hz, in particular greater than 1 kHz or greater than 10 kHz and with the power produced in this manner, can supply the above-described loads with dynamic load impedance. To produce an AC voltage from a direct current (DC) voltage, a circuit which is known as a bridge circuit is often used. Such a bridge circuit may be supplied by a voltage source, a current source or a power-controlled source with rectified current and voltage. In particular with bridge circuits which are operated with a direct current source, in which a predetermined current is therefore conducted into the bridge circuit, overvoltages may occur at the output of the bridge circuit. These overvoltages may also be transmitted to the input side of the bridge circuit. They can damage the AC voltage generating arrangement. The protection of AC voltage generating arrangements from overvoltages is in particular with dynamic loads a problem which is often addressed with various solutions.
DE102008025986A1 describes an overvoltage protection device having a capacitor which has to be discharged by a discharge circuit. The discharge circuit converts the energy into heat. It has to be monitored with regard to the current carrying capacity as it will otherwise overheat. In addition, this circuit can absorb only a limited amount of energy. Excessively frequent states of overvoltage would overload this circuit.